endmill

[jack620]

The end mill is designed for one job only - profiling (cutting with its side) and should never be used to cut with its end

Meh, I've done it plenty of times. Cheap Chinese 4 flute solid carbide end mills to counterbore 8mm pockets into titanium. Nothing else in my armoury was going to do the job. Whatever it takes to get the job done I say.

 

[Jasonb]

The end mill is designed for one job only - profiling (cutting with its side) and should never be used to cut with its end

So what is the point of centre cutting end mills if we can't plunge into a pocket and then start profiling or use them to cut a helical bore down into a pocket before profiling.

I do these things particularly the later quite a lot as does most of industry with their CNC machines. The world has moved on from when there were only 2-flute slot drills or 4-flute endmills with screwed shanks.

 

[L98fiero]

So what is the point of centre cutting end mills if we can't plunge into a pocket and then start profiling or use them to cut a helical bore down into a pocket before profiling.

I do these things particularly the later quite a lot as does most of industry with their CNC machines. The world has moved on from when there were only 2-flute slot drills or 4-flute endmills with screwed shanks.

I agree, it depends a lot on the rigidity of the machine, a very good way of accurately locating a reamed hole is to drill it 10 - 15% undersize and then drill with an endmill that has been ground 2 - 3% under finished size to accurately locate the hole before final reaming to size. Not quite as good as jig boring for location and it takes a reasonably rigid machine to do that but endmills can be and do get used for more than profiling. And yes, while a four flute center cutting endmill is not great at a straight plunge cut, slot drills/2 flute endmills are designed for drilling, especially to start a keyway.

 

[IanN]

Meh, I've done it plenty of times. Cheap Chinese 4 flute solid carbide end mills to counterbore 8mm pockets into titanium. Nothing else in my armoury was going to do the job. Whatever it takes to get the job done I say.

Hi Jack,

You can run across the road blindfolded and get away with it loads of times - it doesn’t mean it is sensible or the right thing to do

Regarding machining titanium - just remember it has the same hardness and “strength” as mild steel, but with the density of aluminium. The only thing to bear in mind is that titanium has low thermal conductivity so will work harden quickly if your tool rubs rather than cuts and you do not use coolant

All the best
Ian

 

[IanN]

So what is the point of centre cutting end mills if we can't plunge into a pocket and then start profiling or use them to cut a helical bore down into a pocket before profiling.

I do these things particularly the later quite a lot as does most of industry with their CNC machines. The world has moved on from when there were only 2-flute slot drills or 4-flute endmills with screwed shanks.

Hi Jason,

We are “two nations separated by a common language”

In the USA you call every end milling cutter an “end mill”. In the we have end mills (which are standard milling cutters designed to cut with their sides, but which fit on the end of the milling arbor) and slot drills which are designed to plunge cut

What you do with your CNC machine in an industrial setting probably bears very little relation to what you do with a hobby machine in an average home workshop - a “hobby mill” may allow you to use a three flute slot drill, but it will not possess the rigidity to allow you to use a four flute slot drill for surfacing operations

All the best,
Ian

 

[jack620]

You can run across the road blindfolded and get away with it loads of times - it doesn’t mean it is sensible or the right thing to do

So now you're saying drilling with an end mill is dangerous/stupid? Those sorts of silly statements are the reason why forum threads so often go off the rails. Please try and keep the discussion sensible.

Regarding machining titanium - just remember it has the same hardness and “strength” as mild steel, but with the density of aluminium.

A popular misconception. Titanium is 60% denser than aluminium. And why are you telling me about the properties of titanium? I've worked with it extensively. Have you?

 

[Dubi]

Respecfully,


I don't go for 'high tech\ stuff but I do gp for elegant solutions.
There is a lot of confusion about what is white simply 'widening a hole' and a respondent to my reply lierally doesn't know what the Hell trhat I was prsattling about.

Years ago, I spent perhaps £30 on Georgee Thomas's Model engineer's Workshop Manual and was impressed on just how cheap( but elegant) his tooling was.
For instance there is vast amount on how to do precision boring as an
arguably superior . THREE of his boring tools are nothing more than a bit of square or rectangular mill steel, an socket screww and a - wait for it---- a broken centre drill on each item.
In other words, I am a crude ill educated Geordie out of **** row and as a quite capable cost account have realised the cost is bluntly, the square root of bugger all!
In the same book, there is a oddly sorted heap of metal which is an adjustable boring head which wil do ball handles as well and the cost was a Model Engineer 40 TPI tap and die.
A few moths ago, I bought a bundle of scrap ms sheet and a few short lengths of EN1A.


Bluntltly, just how cheap do you want to pay for your hobby folks?

Enough from me

Norman

Nice comment, appreciated. Stay safe.

 

[goldstar31]

Nice comment, appreciated. Stay safe.

Thanks Dubi for the succinct but nevertheless wise words.
As I have repeated so many tomes, it is a hobby and we can only make it a continued success by exercising harmony. There os nothing to be gained from behaving otherwise.
So thank you for your courteous understanding.

My best wishes and I hope that you are continuing to enjoy your hobby in what are troublesome enough times for everyone in the World

Norman

 

[jetstuff]

And why are you telling me about the properties of titanium? I've worked with it extensively. Have you?

Jack, please remember that these posts are also for the benefit of those still wanting to learn, not only for those that already know....

 

[jack620]

Jack, please remember that these posts are also for the benefit of those still wanting to learn, not only for those that already know....

It's only of benefit if it's correct jetstuff.

 

[terryd]

Hullo members, any information where I can purchase a .346" 4 flute carbide endmill? have searched the net no result. rrocky

The D bit mentioned in an earleir post would be a perfect solution as you ly need a small diameter hole. I make mine from silver steel (drill rod) hardened and tempered for only the last inch or so. You can turn the drill rod down to any diameter and as accurately as you need. athey can be used as reamers and as accurate boring tools for long accurately centred holes on the lathe especially, as there is much less tendency to twist under the forces invilved unlike normal jobbers fluted drills which tend to try to 'untwist' under htose forces and is a main cause of drill wandering.

My D bits are made to a different style than the one shown earlier and is based on the work of George Thomas (mentioned in an earlier posting by Norman) and they work and work well and can be made easily in the workshop as needed - why wait for the mailman?

Here's one of mine - crude, well used, worn, but still works, like me!. this one is 12mm diameter and in need of a touch on the grindstone.

side profile showing clearance angle - similar to lathe tool

Top view showing non cutting side ground at angle from centre of clearance, doesn't need to be exact if a pilot hole is drilled. I marked an exact centre before hardening using a lathe with a cutting tool set exactly on centre and scribed a line with the D bit in the 3 jaw. Best used on a lathe

Stay safe and healthy

 

[goldstar31]

My D bits are made to a different style than the one shown earlier and is based on the work of George Thomas (mentioned in an earlier posting by Norman) and they work and work well and can be made easily in the workshop as needed - why wait for the mailman?





Stay safe and healthy

Just to be a little different, I used to grind a half just behind your D bit end= to take small amounts of swarf-- after pecking from the tailstock poppet.
No criticism, merely a bit 'doing it my way'

So thank you- and continued best wishes for the demonstrations

Norman

 

[IanN]

So now you're saying drilling with an end mill is dangerous/stupid? Those sorts of silly statements are the reason why forum threads so often go off the rails. Please try and keep the discussion sensible.



A popular misconception. Titanium is 60% denser than aluminium. And why are you telling me about the properties of titanium? I've worked with it extensively. Have you?

Hi Jack,

Thank you for taking the time to reply to my post

I think you misread my comment on crossing the road blindfold - I suggested it was not “sensible or the right thing to do” - you seem to have accidentally misread these words as “dangerous/stupid”

I believe (despite miss reading my reply) that you understand the point I was making. The Original Poster had assumed the best way to do the job was to try and buy special tooling, when the reality (as several people pointed out) was to bore the holes.

By giving good advice the OP ends up wiser, by understanding why certain approaches are not as good as others the OP has a greater chance of succeeding when confronted by problems in the future. As I said in an earlier post - it is the difference between training and education

Regarding my comments about titanium:

I miss understood your statement (apologies) - I thought that you were implying that the fact you were machining titanium was in some way significant as “nothing else in [your] armoury would do the job” (when in reality titanium is no harder to machine than mild steel or aluminium, as long as you use cutting fluid and sharp tools). As you gave the impression that you did not realise this, I tried to help. It is unfortunate that you are offended by my help and take it as some form of insult

You choose to think of titanium as 60% denser than aluminium, I tend to use a “rule of thumb” and group Ti and Al as similar compared to MS - we will just have to agree to differ on our view points, which no doubt come from our different engineering back grounds

Have I machined much Ti? In the 25 year period from 1969 to the mid-1990s, not constantly, but a reasonable amount. Since moving from engineering industrial R and D in to university and college based environment, less so, but my role lecturing in engineering and teaching apprentices requires me to remain at the cutting edge (pun intended)

As you seem easily offended, and I have no desire to upset you, rather than getting in to a bragging contest about how much we have each machined and whose mill has the best motor, I am perfectly happy to say you are better at everything. It makes no difference to me and will presumably make you happy

I recognition of your status, drop me your location and next time I’m in “The Colonies”, if I’m passing your way, I will drop by and buy you a pint. Similarly, if you come to England, offer still stands

All the best,
Ian

 

[Jasonb]

It's only of benefit if it's correct jetstuff.

I don't see anything wrong with correcting misinformation if people are to learn.

For those that do want to learn IanN is probably getting mixed up with weight and density. For example take two bicycle frames of equal strength one made of aluminium and one made of Titanium. They will both weigh approx the same but due to it's strength the denser titanium the frame can be made with much thinner wall tubes. So less material for the same finished strength which cancels out teh fact the Titanium is heavier for the same given volume.

 

[goldstar31]

Some clarity seems merited on 'carbide' and 'titanium''

Both words bear no clear meaning - maven in English.

Cardide means - inn engineering a flammable gas whilst titanium is the replac ement to white lead


Thank You for your expexpected rudition

 

[timo_gross]

Reading in this forum I uncover many new ways to reach the same goal. Lots of information out there. Lots of nay sayers and opinions. Lots of "experts" and "beginners".

they truly believe a bandsaw is the only way to cut a piece of metal

I feel so caught in the act by Ian. "Aren`t fibre lasers the only viable option to cut metal? ... A hacksaw really? It is a constant challenge to judge information, choose the right tool for the right job, use the tool you want to use because it is fun , or work with what you have. I abuse a cnc machine for simple jobs like drilling incl. lengthy setups all the time. My drillpress is a horrible cheap junk without any torque.

A simple picture of a Universal pillar tool made by someone as a fun hobby project causes all sorts of comments. Telling the beginner ( maybe the maker of the tool, or only a spectator ) that he was extremly stupid: "Tapping can only be done with 5 axis machine centers ( Made in Germany, blonde virgin, full moon, blabla )" via "I never broke a tap in my life" to "I can grind a .346 inch 4 flute carbide endmill from a saw cut pine wood blank on my bench grinder, it takes less than 5 min"

@rrocky: Did you find that guy with the magic bench grinder or the magic guy with the bench grinder - done- ?!

Greetings Timo

 

[jack620]

You choose to think of titanium as 60% denser than aluminium...

Choose to think? Titanium is 60% denser than aluminium. That is not open for debate. And you claim to have lectured engineering at university.

As you seem easily offended

On the contrary, I have a hide like a rhinoceros. But I feel duty-bound to point out misinformation and hyperbole when I see it. And there's plenty of it in your posts.

 

[Badhippie]

Put me in the ***** class I clean both my Lathes and my mill with compressed air at a reduced psi. As for the hacksaw yep I know how to use one but why would I use a hacksaw over a band saw or a portaband. I believe in letting my tools do the work for me. Work smarter not harder. Please excuse me for being a newbie at this I have only been doing it since 1986 as a profession. Plunge a hole with a endmill omg how taboo. A endmill is only made to cut on its side I guess I don’t even know what to say about that one ( Center Cut ) Now is it the best tool for making a hole maybe not the best tool but it’s in the top 5. If you want a hole and have the equipment and tools to do it then drill it close and finish it by boring to size. I guess again put me in the ***** class I have made thousands of holes with a center cut endmill.
Most people in here do this as a hobby so to use words like idiots or stupid is completely uncalled for this does nothing for helping a person. Then for us who do this as a profession to hear how stupid we are and have been doing it wrong. Well it’s not the first time I have done something wrong and it won’t be the last time. But I seem to make a damn fine living at it. Now you can call this butt hurt or whatever you want but if anyone knows me I really could care less what a person thinks of me never have cared and never will care. But when someone asks a question how about we try to answer the question to the best of our ability and leave the ******** out ( except for joking with someone that’s always allowed lol ) Thanks for letting me vent I am done now remember these words of wisdom from the Hippie.
When a job becomes work it’s time to find another job.
Thanks Tom

 

[jack620]

Put me in the ***** class I clean both my Lathes and my mill with compressed air at a reduced psi.

Me too. 30psi seems to be about right. Brilliant for blowing chips off tool-holders before returning them to their drawer. I suspect people who make black and white "*****" type statements on forums are textbook/theoretical types with limited real world experience. They should stick to the classroom.

 

[goldstar31]

Me too. 30psi seems to be about right. Brilliant for blowing chips off tool-holders before returning them to their drawer. I suspect people who make black and white "*****" type statements on forums are textbook/theoretical types with limited real world experience. They should stick to the classroom.

Inevitably, there will be an accident or two and whilst the pharmaceutical industry and its shareholders will reap the rewards from their foresight.
I vaguely recall my school days but what little remains sufficed to learn about 'Wise and foolish virgins'. having alternative jobs like St Paul and the bit about the generosity from a despised Samarium.

So dammit, I invested in 'silly sunbathers' and gambled on the odds that the Plagues of Egypt was not a 'one off' and that there would be need for more of the Good Doctor St Lukes.

Far be it from me to offer criticism and I applaud your demand to freely shape your life